Re: Topband: Detuning Relay Flyback Diode

From a relay hold-on point of view, this will perform very similarly to the diode across the relay. David G3UNA - Original Message - From: "Brian Pease" To: Sent: Sunday, December 24, 2017 5:18 PM Subject: Re: Topband: Detuning Relay Flyback Diode I am sure that some r

Re: Topband: Detuning Relay Flyback Diode

I am sure that some rigs use an "open drain" MOSFET instead of a "normal" transistor.  The built-in "body diode" of the MOSFET acts as a built-in snubber for the reverse polarity transient, and should easily handle the current. On 12/24/2017 11:49 AM, Paul Christensen wrote: A single-componen

Topband: Detuning Relay Flyback Diode

A single-component option with the benefits of the combo diode/Zener that Jim described is a “Transorb” device. The link below opens an application note that discusses various forms of coil transient suppression, beginning with passive, then single diode, a combo diode-Zener (mentioned by Jim an

Re: Topband: Detuning Relay Flyback Diode

need for 1N5400 size. David G3UNA - Original Message - From: "Jim Garland" <4cx2...@miamioh.edu> To: Sent: Sunday, December 24, 2017 3:40 PM Subject: Re: Topband: Detuning Relay Flyback Diode I'm always hesitant to challenge anything Jim VE7RF says about amps,

Re: Topband: Detuning Relay Flyback Diode

What's wrong with using an MOV across the coil, with a .1 uf capacitor in parallel with it? That's what I do. The relay opens almost instantly when the coil is de-energized. The value of the MOV should be a few volts above the coil voltage. For example, an 18 volt MOV for a 12 volt coil. 73, Mike

Re: Topband: Detuning Relay Flyback Diode

ode (1n4148) will work just fine. 73, Jim W8ZR On 12/23/2017 10:26 AM, Jim Thomson wrote: Date: Sat, 23 Dec 2017 10:51:57 -0500 From: Brad Denison To:topband@contesting.com Subject: Topband: Detuning Relay Flyback Diode ## I call em back emf diodes.Use a single 1N5408 or 6A10 diode, r

Re: Topband: Detuning Relay Flyback Diode

If you have any diodes in a switch box or the like, be sure to add a bypass cap across the diode - 0.01 uF will do.  Diodes are great harmonic generators (and mixers) and equipment connected to control cables or feed lines often is pretty hot with RF current. That includes rotator controllers,

Re: Topband: Detuning Relay Flyback Diode

ison" To: Sent: Saturday, December 23, 2017 3:51 PM Subject: Topband: Detuning Relay Flyback Diode I have a couple of 6ms 12V Kilovac relays wired up as a detuning circuit during RX. One question comes up before implementation regarding flyback diodes - would they be needed? Seeking o

Topband: Detuning Relay Flyback Diode

Date: Sat, 23 Dec 2017 10:51:57 -0500 From: Brad Denison To: topband@contesting.com Subject: Topband: Detuning Relay Flyback Diode http://w1nt.com> ## I call em back emf diodes.Use a single 1N5408 or 6A10 diode, reverse connected across the 12 vdc winding. Heres the simple fix to SP

Re: Topband: Detuning Relay Flyback Diode

Tim, Yes the end intent is to have the K3 key both an amp and the detuning circuit. Would you happen to have an example of the series diode circuit you are referring to? Seems better to implement this vs. creating relay delay. Thanks, Brad W1NT On Sat, Dec 23, 2017 at 11:05

Re: Topband: Detuning Relay Flyback Diode

to:topband-boun...@contesting.com] On Behalf Of Brad Denison Sent: Saturday, December 23, 2017 10:52 AM To: topband@contesting.com Subject: Topband: Detuning Relay Flyback Diode I have a couple of 6ms 12V Kilovac relays wired up as a detuning circuit during RX. One question comes up before implementation re

Re: Topband: Detuning Relay Flyback Diode

a problem after installing 1N400X fly-back diodes. Paul, W9AC -Original Message- From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Brad Denison Sent: Saturday, December 23, 2017 10:52 AM To: topband@contesting.com Subject: Topband: Detuning Relay Flyback Diode I have a cou

Re: Topband: Detuning Relay Flyback Diode

Whether a flyback diode is needed depends on what is driving the relay and whether it needs snubbing. Adding a flyback diode substantially lengthens the time it takes a relay to open, which may or may not be an issue. What was a 6ms relay will become several times longer on open. There are better

Topband: Detuning Relay Flyback Diode

I have a couple of 6ms 12V Kilovac relays wired up as a detuning circuit during RX. One question comes up before implementation regarding flyback diodes - would they be needed? Seeking opinions on this question. The relays are powered during TX and not powered for RX direct keyed by the radio wi